*{
    padding: 0;
    margin: 0;
    list-style: none;
}
html,body{
    width:100% ;
    height:100% ;
}
.wrapper{
    display: flex;
    justify-content: center;
    align-items: center;
    width:100% ;
    height:100% ;
    background-color: #000;
    color:#fff;
    
}
.content{
    display: flex;
    justify-content: space-between;
    align-items: center;
    width:80%;
    height:80%;
    
}
.item{
    width:24.5%;
    height:100%;
    overflow: hidden;
    border-radius: 20px;
    background-color: #333;
    transition: height 0.5s linear 0.5s,width 0.5s linear;
}
.active{
    width:100%;
    
}
.wrapper-active .item{
    transition: height 0.5s linear,width 0.5s linear 0.5s;
}
.wrapper-active .item:not(.active){
    width:0%;
    height:0%;
    
}
.item .inner{
    position: relative;
    width:100%;
    height:100%;
    border-radius: 20px;
    overflow: hidden;
    transition: transform 0.5s linear;
}
.active #bg{
    background-position: top;
}

.item:nth-of-type(2) .inner{
    transition-delay: 0.1s;
}
.item:nth-of-type(3) .inner{
    transition-delay: 0.2s;
}
.item:nth-of-type(4) .inner{
    transition-delay: 0.3s;
}
.init .item .inner{
    transform: translate3d(0,100%,0);
}

.item .bg{
    width:100%;
    height:100%;
    background-size:cover;
    background-position: top; 
    opacity: 0.7; 
    
}

.item:nth-of-type(1) .bg{
    background-image: url("../img/6.jpg");
    background-position: 80%; 
}
.item:nth-of-type(2) .bg{
    background-image: url("../img/7.jpg");
    background-position: 10%;
}
.item:nth-of-type(3) .bg{
    background-image: url("../img/8.jpg");
    background-position: 10%;
}
.item:nth-of-type(4) .bg{
    background-image: url("../img/9.jpg");
    background-position: right; 
}
.item .title{
    position: absolute;
    top:50%;
    left:50%;
    transform: translate(-50%,-50%);
}
.wrapper .item .title{
    transition:opacity 0.2s linear 1s;
}
.wrapper-active .item .title{
    opacity: 0;
    transition: opacity 0.2s linear;
}

.item .title h2{
    font-size: 14px;
}
.item:hover .title h2{
    font-size:18px;
    transition: font-size 0.2s linear;
}
.item:hover .bg{
    opacity:1 ;
}
.item .dis{
    position: absolute;
    top:30px;
    width: 100%;
    height:30px;
    opacity: 0;
    transition: opacity 0.2s linear;
}
.item .header{
    float: left;
    margin-left: 30px;
    line-height: 30px;
    font-size:20px;
}
.item .close{
    position: relative;
    float: right;
    margin-right: 30px;
    width:30px;
    height:30px;
    
}
.item .close:before,
.item .close:after{
    content:"";
    position: absolute;
    top:50%;
    left:0;
    width:30px;
    height:2px;
    margin-top:-1px;
    background: #fff;
    
}
.item .close:before{
    transform: rotate(45deg);
}
.item .close:after{
    transform: rotate(-45deg);
}
.active .dis{
    opacity: 1;
    transition:opacity 0.2s linear 1s;
}
